The present invention relates to a cover construction, and, more particularly, to a cap-like cover member for covering an air bag or gas cushion installation disposed inside a steering wheel of a motor vehicle with the cap-like cover member being made of an elastic material and being adapted to be clipped on to a baseplate and being adapted to rip or tear open along predetermined breaking lines when the air bag or gas cushion is deployed and unfold like a hinge.
In addition to stylistic constraints, a cover member of the aforementioned type must meet special requirements with respect to the strength thereof within a wide temperature range especially when the cover member is subjected to the forces which are limited to a short period of time when the air bag of the air bag installation is deployed. Thus, the material and wall thickness of the cover member must be made such that the cover rips open exactly along the predetermined breaking lines even at a low inflation pressure thereby enabling the air bag to be freely deployed without delay. On the other hand, the cover member must also be so constructed that it withstands the load to which it is exposed on opening without tearing and without scattering fragments. Additionally, the cover member must be easy to install and must likewise be easy to remove if necessary; however, the ease of installation must not conflict with the firm fit of the cover member.
The aim of the present invention essentially resides in providing a cover, of an elastic material, for an air bag installation disposed inside a steering wheel wherein deformation phenomena caused by an inflation of the stored air bag are prevented even at extremely high temperatures and forces.
In accordance with the cover member of the present invention, the cover member is constructed so as to ensure that even when the material begins to become brittle and at low temperatures, the cover member will reliably tear open. For this purpose, a cover member of the type described hereinabove is proposed, wherein, according to the present invention, a pulled down edge of the mounted cover member is prevented by retainers from exhibiting deformation phenomena when it is subjected to outwardly directed forces such as occur upon an inflation of the stored air bag.
In accordance with advantageous features of the present invention, the retainers are provided in the form of a highly tear-resistant continuous band which is embedded in the elastic material in a vicinity of an edge of the cover member. To achieve an especially good anchoring of the continuous band to the adjacent material, at least some sections of the continuous band are provided with a coarsely constructed fabric covering.
The cover of the present invention that tears along predetermined breaking lines so that, upon opening up, the cover member forms two flaps which are displaced outwardly so as to enable the stored air bag to be inflated. To increase the strength of the cover member in a vicinity of the flaps as well as the strength of the pivot axis of such flaps, the continuous band may be provided, on two opposite sides thereof, with fabric flaps sewn thereto. The fabric flaps, may, for example, be embedded in the elastic material in a vicinity of the flaps of the cover when the cover is manufactured.
It is also possible in accordance with the present invention, for the purposes of reinforcement, to provide retainers in the form of angled members mounted on the baseplate and abutting outer areas of the pulled down edge of the cover member. The angled members may be secured to a baseplate by fasteners such as, for example, screws with heads of the screws being protected against inadvertent loosening by, for example, paint.
Accordingly, it is an object of the present invention to provide a cover member for an air bag installation arranged at a steering wheel which avoids, by simple means, shortcomings and disadvantages encountered in the prior art.
Another object of the present invention resides in providing a cover member for an air bag installation arranged at a steering wheel which prevents the cover member from exhibiting deformation phenomena when the air bag installation is triggered.
A further object of the present invention resides in providing a cover member for an air bag installation arranged at a steering wheel which will reliably open when the air bag installation is triggered.
Yet another object of the present invention resides in providing a cover member for an air bag installation arranged at a steering wheel which ensures that no parts of the installation comes loose when the cover member is opened.
A still further object of the present invention resides in providing a cover member for an air bag installation arranged at a steering wheel which is simple in construction and therefore relatively inexpensive to to manufacture.
Another object of the present invention resides in providing a cover member for an air bag installation arranged at a steering wheel which ensures the reliable functioning of the air bag installation under all operating conditions.
These and other objects, features and advantages of the present invention will become more apparent when taken in connection with the accompanying drawings which show, for the purposes of illustration only, two embodiments in accordance with the present invention.